CodeMirror.defineMode("ruby", function (config, parserConfig) {
    function wordObj(words) {
        var o = {};
        for (var i = 0, e = words.length; i < e; ++i) o[words[i]] = true;
        return o;
    }

    var keywords = wordObj([
        "alias", "and", "BEGIN", "begin", "break", "case", "class", "def", "defined?", "do", "else",
        "elsif", "END", "end", "ensure", "false", "for", "if", "in", "module", "next", "not", "or",
        "redo", "rescue", "retry", "return", "self", "super", "then", "true", "undef", "unless",
        "until", "when", "while", "yield", "nil", "raise", "throw", "catch", "fail", "loop", "callcc",
        "caller", "lambda", "proc", "public", "protected", "private", "require", "load",
        "require_relative", "extend", "autoload"
    ]);
    var indentWords = wordObj(["def", "class", "case", "for", "while", "do", "module", "then",
        "catch", "loop", "proc", "begin"]);
    var dedentWords = wordObj(["end", "until"]);
    var matching = {"[": "]", "{": "}", "(": ")"};
    var curPunc;

    function chain(newtok, stream, state) {
        state.tokenize.push(newtok);
        return newtok(stream, state);
    }

    function tokenBase(stream, state) {
        curPunc = null;
        if (stream.sol() && stream.match("=begin") && stream.eol()) {
            state.tokenize.push(readBlockComment);
            return "comment";
        }
        if (stream.eatSpace()) return null;
        var ch = stream.next();
        if (ch == "`" || ch == "'" || ch == '"' ||
            (ch == "/" && !stream.eol() && stream.peek() != " ")) {
            return chain(readQuoted(ch, "string", ch == '"' || ch == "`"), stream, state);
        } else if (ch == "%") {
            var style, embed = false;
            if (stream.eat("s")) style = "atom";
            else if (stream.eat(/[WQ]/)) {
                style = "string";
                embed = true;
            }
            else if (stream.eat(/[wxqr]/)) style = "string";
            var delim = stream.eat(/[^\w\s]/);
            if (!delim) return "operator";
            if (matching.propertyIsEnumerable(delim)) delim = matching[delim];
            return chain(readQuoted(delim, style, embed, true), stream, state);
        } else if (ch == "#") {
            stream.skipToEnd();
            return "comment";
        } else if (ch == "<" && stream.eat("<")) {
            stream.eat("-");
            stream.eat(/[\'\"\`]/);
            var match = stream.match(/^\w+/);
            stream.eat(/[\'\"\`]/);
            if (match) return chain(readHereDoc(match[0]), stream, state);
            return null;
        } else if (ch == "0") {
            if (stream.eat("x")) stream.eatWhile(/[\da-fA-F]/);
            else if (stream.eat("b")) stream.eatWhile(/[01]/);
            else stream.eatWhile(/[0-7]/);
            return "number";
        } else if (/\d/.test(ch)) {
            stream.match(/^[\d_]*(?:\.[\d_]+)?(?:[eE][+\-]?[\d_]+)?/);
            return "number";
        } else if (ch == "?") {
            while (stream.match(/^\\[CM]-/)) {
            }
            if (stream.eat("\\")) stream.eatWhile(/\w/);
            else stream.next();
            return "string";
        } else if (ch == ":") {
            if (stream.eat("'")) return chain(readQuoted("'", "atom", false), stream, state);
            if (stream.eat('"')) return chain(readQuoted('"', "atom", true), stream, state);
            stream.eatWhile(/[\w\?]/);
            return "atom";
        } else if (ch == "@") {
            stream.eat("@");
            stream.eatWhile(/[\w\?]/);
            return "variable-2";
        } else if (ch == "$") {
            stream.next();
            stream.eatWhile(/[\w\?]/);
            return "variable-3";
        } else if (/\w/.test(ch)) {
            stream.eatWhile(/[\w\?]/);
            if (stream.eat(":")) return "atom";
            return "ident";
        } else if (ch == "|" && (state.varList || state.lastTok == "{" || state.lastTok == "do")) {
            curPunc = "|";
            return null;
        } else if (/[\(\)\[\]{}\\;]/.test(ch)) {
            curPunc = ch;
            return null;
        } else if (ch == "-" && stream.eat(">")) {
            return "arrow";
        } else if (/[=+\-\/*:\.^%<>~|]/.test(ch)) {
            stream.eatWhile(/[=+\-\/*:\.^%<>~|]/);
            return "operator";
        } else {
            return null;
        }
    }

    function tokenBaseUntilBrace() {
        var depth = 1;
        return function (stream, state) {
            if (stream.peek() == "}") {
                depth--;
                if (depth == 0) {
                    state.tokenize.pop();
                    return state.tokenize[state.tokenize.length - 1](stream, state);
                }
            } else if (stream.peek() == "{") {
                depth++;
            }
            return tokenBase(stream, state);
        };
    }

    function readQuoted(quote, style, embed, unescaped) {
        return function (stream, state) {
            var escaped = false, ch;
            while ((ch = stream.next()) != null) {
                if (ch == quote && (unescaped || !escaped)) {
                    state.tokenize.pop();
                    break;
                }
                if (embed && ch == "#" && !escaped && stream.eat("{")) {
                    state.tokenize.push(tokenBaseUntilBrace(arguments.callee));
                    break;
                }
                escaped = !escaped && ch == "\\";
            }
            return style;
        };
    }

    function readHereDoc(phrase) {
        return function (stream, state) {
            if (stream.match(phrase)) state.tokenize.pop();
            else stream.skipToEnd();
            return "string";
        };
    }

    function readBlockComment(stream, state) {
        if (stream.sol() && stream.match("=end") && stream.eol())
            state.tokenize.pop();
        stream.skipToEnd();
        return "comment";
    }

    return {
        startState: function () {
            return {
                tokenize: [tokenBase],
                indented: 0,
                context: {type: "top", indented: -config.indentUnit},
                continuedLine: false,
                lastTok: null,
                varList: false
            };
        },

        token: function (stream, state) {
            if (stream.sol()) state.indented = stream.indentation();
            var style = state.tokenize[state.tokenize.length - 1](stream, state), kwtype;
            if (style == "ident") {
                var word = stream.current();
                style = keywords.propertyIsEnumerable(stream.current()) ? "keyword"
                    : /^[A-Z]/.test(word) ? "tag"
                    : (state.lastTok == "def" || state.lastTok == "class" || state.varList) ? "def"
                    : "variable";
                if (indentWords.propertyIsEnumerable(word)) kwtype = "indent";
                else if (dedentWords.propertyIsEnumerable(word)) kwtype = "dedent";
                else if ((word == "if" || word == "unless") && stream.column() == stream.indentation())
                    kwtype = "indent";
            }
            if (curPunc || (style && style != "comment")) state.lastTok = word || curPunc || style;
            if (curPunc == "|") state.varList = !state.varList;

            if (kwtype == "indent" || /[\(\[\{]/.test(curPunc))
                state.context = {prev: state.context, type: curPunc || style, indented: state.indented};
            else if ((kwtype == "dedent" || /[\)\]\}]/.test(curPunc)) && state.context.prev)
                state.context = state.context.prev;

            if (stream.eol())
                state.continuedLine = (curPunc == "\\" || style == "operator");
            return style;
        },

        indent: function (state, textAfter) {
            if (state.tokenize[state.tokenize.length - 1] != tokenBase) return 0;
            var firstChar = textAfter && textAfter.charAt(0);
            var ct = state.context;
            var closing = ct.type == matching[firstChar] ||
                ct.type == "keyword" && /^(?:end|until|else|elsif|when|rescue)\b/.test(textAfter);
            return ct.indented + (closing ? 0 : config.indentUnit) +
                (state.continuedLine ? config.indentUnit : 0);
        },
        electricChars: "}de" // enD and rescuE

    };
});

CodeMirror.defineMIME("text/x-ruby", "ruby");

